A product rating through a vote/poll option.
People can ad a micro hopup an everyone can make his/her vote about the product. It can avoid long issues on the forums about some hop-ups if a voting rate can make it clear if it is worth it.
Maybe a Pricewatch ?
http://www.tweakers.net (computer related) does have a pricewatch where shops can ad their price to a product so people can see what item can be ordered where and what the costs are (inc/ex VAT and shipping costs)
Like this for a ATI videocard:
http://www.tweakers.net/pricewatch/36925